The present invention generally relates to frangible seals, i.e. breakable closures, for allowing fluid communication in a sealed conduit. More particularly, the invention relates to a frangible seal for providing fluid communication between a plurality of isolated containers, for example blood bags.
In a variety of applications, it is desirable to separately store components of a mixture for subsequent mixing. The components can be separated and isolated by what hereinafter generically will be referred to as a frangible seal, which is ruptured to provide communication between containers in which the separate components are stored.
Additionally, in the area of blood transfusions, whole blood is rarely used to perform a transfusion. Instead, in order to make an effective use of the blood, it is separated into components and the various components are placed in separate bags.
To this end, there has been provided a so-called multiple bag which is integral, closed and sterile-sealed, and may be manipulated wholly from outside itself and in which a plurality of plastic blood bags are mutually connected by means of connection tubes. Whole blood is collected into a collecting bag and thus, subject to centrifugation thereby to separate the components. However, to prevent unseparated blood from scattering into a connection tube, a rupturable seal is provided.
In another related field, a procedure known as continuous ambulatory peritoneal dialysis is used to treat End Stage Renal Disease. The continuous ambulatory peritoneal dialysis procedure is intended to be a patient self-care technique once a catheter is surgically implanted in the patient. In this procedure, a dialysis solution is infused into the peritoneal cavity of the patient. The dialysis solution is stored in a bag that can be connected to the catheter.
In both of these fields, frangible seals and flexible tubes are used to effect communication between the blood bags or the dialysis solution and the catheter, respectively.
In this regard, in U.S. Pat. No. 4,007,738, there is discussed a mechanism for allowing blood bags to communicate with each other comprising a connection pipe; a connection tube for connecting a first blood bag to a second blood bag, the connection tube being fitted into and secured to the connection pipe having a sealed portion, one end thereof on the side of the second blood bag being fitted into and secured to the connection tube; and a breakable small thickness section formed at the communication pipe between the sealed portion and the secured end thereof. Communication between the first and second bags is rendered effective by breaking the communication pipe at the small thickness portion.
In U.S. Pat. No. 4,181,140, there is disclosed a frangible resealable closure for a flexible tube having hold open means. Valve means in a flexible tube, for example, tubing for connecting blood bags, are provided which comprises a tubular portion having a closed end, and an elongated generally rigid member carried on the exterior of the closed end and positioned within the flexible tube. Frangible means are provided to permit the opening of the closed end by manual manipulation of the elongated member from outside of the flexible tube.
The elongated, rigid member is adapted to fit in sealing relationship within the tubular portion after opening of the closed end, to permit resealing of the valve. The elongated, generally rigid member carries longitudinal vanes to provide flow channels along its length. A pair of the vanes in opposed relationship extend rearwardly of the end of the central portion of the rigid member, and the flexible tube defines a bore portion positioned to receive and resiliently hold the opposed vanes when the frangible means is broken and the rigid member is separated from the tubular portion.
It is discussed that the vanes may be of unequal length. The flexible tube surrounding the rigid member may then define a conical portion, positioned to receive and resiliently hold the longer vanes after the frangible means have been broken and the rigid member separated from the tubular portion.
The elongated, generally rigid member also includes a tapered portion for fitting within the bore of the tubular portion after opening for reclosing the structure again. Thus, the discussed frangible seal also functions as a frangible resealable closure.
However, studs are provided to project outwardly from the elongated, rigid member to prevent the accidental complete insertion of the elongated member into the bore which could render the removal of the member difficult at a later time. The studs bear against the end of the tubular portion when the elongated member is inserted into its proper depth, preventing further insertion.
In U.S. Pat. No. 4,294,247 there is discussed another frangible, resealable closure for a flexible tube.
In U.S. Pat. No. 4,340,049 there is discussed another frangible seal in the form of a break-away valve comprising two parts: a tubular portion with a closed end; and an elongated, generally rigid handle breakably attached to the closed end. The elongated handle has projections which frictionally contact the interior surface of the flexible tube and prevent the elongated handle from moving back into a closed position once the elongated handle has been broken.
The valve may be used in conjunction with tubing and a plastic container of a dialysis solution. The valve is opened by breaking away the elongated, generally rigid handle and moving (i.e., "walking") the rigid handle down the tube by folding the tube back and forth upon itself. The projections of the rigid break-away handle have sufficient frictional contact with the inside of the tube to assure that the handle will not move back into contact with the tubular portion, and the valve will remain open.